he was 3betting alot so i thought JTo could fall into the 4bet bluff range. he bets pretty small on the turn, inclines me to believe he could have some overcards or spade or sort of weak hand. i called with the plan of shoving the turn on broadways or if I hit or for value with spades.

thinking back, i dont think there is alot of worse spade hands in his range for 3bet/calling, the worse in his range was probably T
or better so perhaps checking back the river could be better? or should i bet small for value from non-spade paired hands?

Preflop: I would call here. I think villain probably has ~20% range here. That's like a typical 3bet range in a HU match, and in a HU match most people are flatting JTo here. I don't see why we shouldn't do the same in a BB vs BU situation.

Anyway bet size is pretty small, 2bb->6bb. With only 4bb more to call, I think calling is extremely favourable. If bet size was larger I would consider 4betting.

Flop: I absolutely do not get this flop check. It's not as though you have Ace high. We want to bet here immediately, 5$-6$ should suffice. What do you think his range is here? You gave him super good odds preflop, so he has a ton of junk here, and he will have to fold most of his non Ace high broadways too, as well as 98s T9s 97s 76s type of hands.

Rest of the hand is irrelevant, i think we should never have gotten ourselves into this spot in the first place.